Over the last 50 years, cancer has become a leading cause of death in the developed world. Hepatocellular carcinoma is the most common primary liver tumor and in countries where hepatitis B infection is prevalent, it is a leading cause of death. Cancer research involving cell transplantation primarily use mice. These assays are slow and require immunosuppressed mice to prevent cell rejection. Clonogenic assays in which cells are cultured in a petri dish or culture flask are also used for drug screening. Cells, however, frequently fail to divide in culture and results are also not predictive of drug performance in humans. This Phase I SBIR aims to develop a whole animal model for screening drugs against hepatocellular carcinoma using zebrafish (Danio rerio) embryos. The transparency of the embryo and the ease with which drugs can be introduced into the zebrafish are inherent advantages of the zebrafish model. PROPOSED COMMERCIAL APPLICATIONS: Therapeutic approaches for cancer generate in excess of $10B in worldwide revenue. By providing a rapid, high throughput, automated method for screening drugs, the zebrafish assay will facilitate drug development and reduce the costs associated with it.